KR20140042685A - Liquid crystal display deviced and driving method thereof - Google Patents

Abstract

The present invention relates to a liquid crystal display device, more particularly, to a liquid crystal display device which is capable of jumping a polarity pattern with a predetermined number of frames and jumping an FRC pattern with the other predetermined number of frames, and a driving method thereof. For the purpose, a liquid crystal display device according to the present invention comprises: a pattern on which gate lines and data lines are formed; an image persistence removal device for generating an FRC pattern which is to be added to an input image and a polarity pattern which outputs the input image and combining the two patterns into one when the interlace input image is inputted from an external system and generating at least two groups which are formed in parallel to the gate lines in a period of one frame; and a data driving unit for converting image data inputted from the image persistence removal device into a data voltage, reversing the polarity of the data voltage based on the polarity pattern and outputting the data voltage through the data lines. [Reference numerals] (AA) First frame; (BB) Second frame; (CC) Third frame; (DD) Fourth frame; (EE) Fifth frame

Description

Liquid crystal display and its driving method {LIQUID CRYSTAL DISPLAY DEVICED AND DRIVING METHOD THEREOF}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device and a driving method thereof for removing an afterimage from a liquid crystal display device using an FRC method and an interlaced scan method.

2. Description of the Related Art As various portable electronic devices such as a mobile phone, a PDA, and a notebook computer are developed, there is a growing demand for a flat panel display device applicable to the portable electronic device.

As a flat panel display device, a liquid crystal display device, a plasma display liquid crystal panel (Plasma Display Panel), a field emission display device (FED emission display device), a light emitting display device (Light Emitting Display Device) have.

In particular, a liquid crystal display (LCD) is an apparatus for displaying an image using optical anisotropy of a liquid crystal, and is widely used because of its advantages such as thinness, small size, low power consumption and high image quality.

FIG. 1 is an exemplary diagram for describing a state in which an afterimage occurs due to polarity bias in cumulative frames in a conventional liquid crystal display using the FRC method and the interlaced scan method.

The method of displaying an image is called an interlaced scan (interlaced scan) method (hereinafter simply referred to as an 'interlaced method') and a progressive scan (hereinafter referred to as 'progressive method'). The interlaced method, which has a small amount of data, has been widely used from the past to the present, but the progressive method has been widely used in recent years.

Frame rate control (hereinafter, simply referred to as 'FRC') is a method of reducing the number of data bits to reduce the number of data transmission lines and compensating for image degradation. .

The AH-IPS mode is also called a FFS (Fringe Field Switching) mode in which the pixel electrode and the common electrode are formed to be spaced apart from each other with an insulating layer interposed therebetween. In the AH-IPS mode liquid crystal display, one electrode is formed in a plate shape, the other electrode is formed in a finger shape, and a fringe field is generated between the two electrodes. The arrangement of the liquid crystal layer is controlled.

On the other hand, in a liquid crystal display device which receives an input image generated by an interlaced method from an external system and outputs an image through a panel in an interlaced scan method, afterimages are generated by using the interlaced method. This phenomenon occurs severely in the liquid crystal display device driven in the AH-IPS mode. Therefore, various methods for removing the afterimage caused by the use of the interlaced method have been developed and studied.

In addition, even in a liquid crystal display device that outputs an image using the FRC method, an afterimage occurs due to the use of the FRC method. This phenomenon is seriously generated in the liquid crystal display device driven in the AH-IPS mode. Therefore, various methods for removing afterimages by using the FRC method have been developed and studied.

However, in the liquid crystal display device employing both the interlaced method and the FRC method, the afterimage generated by the interlaced method and the FRC method is different from the afterimages generated in the liquid crystal display device to which the interlaced method and the FRC method are applied. There is a difference.

Therefore, even if there are methods for solving the afterimage in the interlaced method and the afterimage in the FRC method, both the interlaced method and the FRC method are applied by simply combining these methods. It is not possible to remove the afterimage generated in the liquid crystal display.

Afterimages generated in the liquid crystal passivation apparatus, to which both the interlaced method and the FRC method are applied, may be caused by various causes. In particular, polarity bias in a cumulative frame is known as a serious cause of the afterimage.

The reason why an afterimage occurs due to polarity bias in a liquid crystal display using both an interlaced method and an FRC method will be described with reference to FIG. 1. In FIG. 1, the first line (X) is input images input to the first to fourth frames by the interlaced method, the second line (Y) is FRC patterns repeated every four frames, and the third line (Z). ) Denotes panel polarity of the first to fourth frames.

The method of calculating the polarity bias at each pixel of the panel is as shown in Equation 1 below.

According to Equation 1, the polarity of the first pixel P1 of the panel shown in FIG. 1 is calculated as shown in Equation 2.

That is, if there is an input image, it is set to 1, if there is no input image, it is set to 0, Black is set to 0, White is set to 1 in the FRC pattern, and the panel polarity is negative. Let the case be (-1) and the case of panel polarity (+) be (+1).

First, the first pixel in the first frame has an input image of 1, an FRC pattern of 0, and a panel polarity of (+1).

Next, the first pixel in the second frame has an input image of 0, an FRC pattern of 0, and a panel polarity of (-1).

Next, the first pixel in the third frame has an input image of 1, an FRC pattern of 1, and a panel polarity of (+1), so that the polarity value is 1 as a whole.

Finally, since the first pixel in the fourth frame has an input image of 0, an FRC pattern of 0, and a panel polarity of (-1), the polarity value of the first pixel is zero.

Therefore, the polarity of the first pixel P1 during four frames becomes 1 (= 0 + 0 + 1 + 0).

According to Equation 1 and the method described above, the polarity of the second pixel P2 of the panel is 0, as shown in Equation 3 above.

On the other hand, by examining the polarity of all the pixels using the method as described above, as shown in (S) of FIG. That is, in the liquid crystal display device using both the interlaced method and the FRC method, polarity bias of +1 or -1 is generated every four frames. This polarity bias continues to occur even if the frame persists.

When the polarity bias is generated as described above, afterimage may occur due to deterioration of the panel, and thus, the quality of the liquid crystal display may be degraded.

In the above, a case in which polarity bias is generated when an input image generated in an interlaced manner from an external system is input has been described. However, even when an input image generated in a progressive manner is input from an external system, polarity bias as described above may occur, and thus, the quality of the liquid crystal display may be degraded. That is, when the input image generated by the progressive method forms a specific pattern, polarity bias as described above may occur.

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above-mentioned problem, and provides a liquid crystal display device and a driving method thereof, which can jump a polar pattern every predetermined frame number and jump an FRC pattern every other predetermined frame number. Let it be technical problem.

The present invention has been proposed to solve the above-described problem, and when the input image generated by the progressive method is input, it is determined whether polarity bias is generated by determining whether polarity is biased in at least two or more preset pixels. In this case, it is a technical object of the present invention to provide a liquid crystal display device and a method of driving the same, wherein the polarity pattern can be jumped every predetermined frame number and the FRC pattern can be jumped every other predetermined frame number.

According to an aspect of the present invention, there is provided a liquid crystal display device including: a panel in which gate lines and data lines are formed; When an interlaced input image is received from an external system, an FRC pattern to be added to the input image and a polar pattern for outputting the input image are generated and formed as a group, and formed in parallel with the gate lines during one frame. Afterimage removal apparatus for generating at least two or more of the groups; And a data driver for converting image data input from the afterimage removing device into a data voltage, inverting the polarity of the data voltage based on the polar pattern, and outputting the data data to the data lines.

According to another aspect of the present invention, there is provided a liquid crystal display device including: a panel in which gate lines and data lines are formed; Receiving a progressive input image or an interlaced input image and determining whether the input image causes an afterimage caused by polarity bias, and when determining that the afterimage is caused by polarity bias, An afterimage removing device for converting the input image so as not to cause the image and outputting the converted image data; And a data driver for converting the image data input from the afterimage removing device into a data voltage and inverting the polarity of the data voltage based on the polar pattern and outputting the data lines to the data lines.

According to an aspect of the present invention, there is provided a method of driving a liquid crystal display device. When an interlace input image is received from an external system, an afterimage removing device may add an FRC pattern to be added to the input image, and a polarity for outputting the input image. Generating a pattern to form a group, and generating at least two groups to be output during one frame; The afterimage removing apparatus converts the input image based on the FRC pattern to generate the image data, and generates a POL signal corresponding to the polar pattern to generate the image data and the pole signal. Transmitting to a driver; And changing, by the data driver, the image data to a data voltage, converting the polarity of the data voltage according to the pole signal, and outputting the polarity of the data voltage to a gate line of the panel.

According to another aspect of the present invention, there is provided a method of driving a liquid crystal display device, including: receiving a progressive input image or an interlaced input image; Determining whether the input image causes an afterimage caused by polarity bias; If it is determined that the input image causes an afterimage caused by polarity bias, converting the input image so as not to cause an afterimage due to polarity bias, and outputting the converted image data; If it is determined that the input image does not cause an afterimage due to polarity bias, realigning the input image according to a panel and outputting rearranged image data; And converting the image data into a data voltage and outputting the data lines to data lines formed in the panel.

According to the present invention, after the polarity pattern is jumped for each predetermined number of frames and the FRC pattern is jumped for another predetermined number of frames, residual images due to polarity bias caused when the interfaced method and the FRC method are simultaneously applied can be eliminated. .

That is, according to the present invention, the polarity shift in the sub-pixel during the cumulative frame can be prevented by changing the change order of the polarity pattern and the FRC pattern at regular intervals. For this reason, the present invention can eliminate the afterimage caused by the polarity bias caused when the interlaced and FRC methods are applied by the interlace input.

In addition, the present invention is to determine whether the polarity bias is generated in the state that the input image generated by the progressive method is input, if it is determined that the polarity bias is generated, by changing the polarity pattern, to remove the residual image due to the polarity bias Can be.

1 is an exemplary view for explaining a state in which an afterimage occurs due to polarity bias in cumulative frames in a conventional liquid crystal display using the FRC method and the interlaced scan method.
2 is an exemplary view for explaining a state in which the FRC pattern and the polar pattern is changed by the liquid crystal display device and the driving method thereof according to the present invention.
3 to 6 are exemplary views for explaining a polarization bias phenomenon during a cumulative frame in the liquid crystal display according to the present invention.
7 is a configuration diagram of an embodiment of an afterimage removing apparatus applied to a liquid crystal display according to the present invention.
8 is a configuration diagram of an embodiment of a liquid crystal display according to the present invention.
9 is a configuration diagram of an embodiment of a data driver applied to a liquid crystal display according to the present invention.
10 is a flowchart illustrating an embodiment of a method of driving a liquid crystal display device according to the present invention.
11 is a flowchart illustrating still another embodiment of a method of driving a liquid crystal display device according to the present invention;
12 is a configuration diagram of still another embodiment of the afterimage removing apparatus applied to the liquid crystal display according to the present invention;
13 is an exemplary view showing positions of representative pixels selected in a panel applied to a liquid crystal display according to the present invention.
14 is an exemplary view illustrating a method of calculating polarity values of representative pixels in a liquid crystal display driving method according to the present invention.
15 is an exemplary view showing a range of thresholds applied to a method of driving a liquid crystal display according to the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is an exemplary view for explaining a state in which the FRC pattern and the polarity pattern are changed by the liquid crystal display and the driving method thereof according to the present invention.

The present invention relates to a liquid crystal display and a driving method thereof for removing an afterimage occurring when both the interlaced and FRC modes are applied in the AH-IPS mode.

As an image display method, there are an interlaced method and a progressive method. An interlaced method having a small amount of data has been widely used from the past to the present, but a progressive method has been widely used in recent years.

Among these, the interlaced method is a method that has been used since the analog method was used. For example, about 30 images per second are taken as 60 images, and then the divided halves are combined and output as 30 sheets. to be. That is, the interlaced method captures 60 frames per second when shooting, but splits them in half when recording, and shows 60 scenes in 30 when playing on a television.

The FRC method reduces the number of bits of data, reduces the number of data transmission lines, and compensates for deterioration in image quality. The FRC method compensates for the loss by increasing the number of gradations that can be expressed using the FRC pattern while reducing the number of bits of digital image data input to the source drive IC of the data driver.

In the liquid crystal display device using the AH-IPS mode, the pixel electrode and the common electrode are formed spaced apart from each other with an insulating layer interposed therebetween. In the AH-IPS mode liquid crystal display, one electrode is formed in a plate shape, the other electrode is formed in a finger shape, and a fringe field is generated between the two electrodes. The arrangement of the liquid crystal layer is controlled.

As mentioned in the related art, when the interlaced method and the FRC method are applied together in a liquid crystal display, polarity bias is generated in each pixel at every predetermined frame interval, for example, at every four frame interval. This polarization bias serves to deteriorate the panel so that an afterimage appears. As a result of testing for each mode of the liquid crystal display, afterimages caused by such polarity bias are generated in particular in the AH-IPS mode.

In order to solve this problem, the present invention, as illustrated in FIG. 2, jumps the polar pantone POL PT every predetermined number of frames, and jumps the FRC pattern FRC PT every other predetermined number of frames, thereby providing an interface. It eliminates afterimages caused by polarity bias caused by the hard drive and FRC method. The present invention is intended to remove afterimages caused by polarity bias caused in the AH-IPS mode, but is not limited to the AH-IPS mode.

First, the present invention outputs by jumping the FRC pattern (FRC PT) for each predetermined number of frames, as shown in Table 1 below.

For example, when there are four FRC patterns C, D, A, and B, as shown in Table 1, the four FRC patterns are sequentially in the order of C, D, A, and B up to the fourth frame. When the change from the fourth frame to the fifth frame, instead of the C FRC pattern, the D FRC pattern is output.

The C FRC pattern should be output after the B FRC pattern of the fourth frame, but the present invention outputs the D FRC pattern by jumping the C FRC pattern. That is, in Table 1, the FRC pattern is jumped and output every four frames.

The present invention can be changed to various frames in addition to four frames. For example, when the polar pattern POL PT to be described below is changed every 2n frames, the FRC pattern may be jumped every 2n × 2m frames. Here, n is a natural number starting from 1, and m is also a natural number starting from 1.

Second, as shown in Table 2 below, the polarity pattern POL PT is jumped and output for each other predetermined number of frames. In the following description, the polar pattern POL PT may be referred to as a set of POL signals for image data output through a panel during one frame. That is, the polar pattern indicates the polarity of the data voltage of each pixel of the image data output through the panel during one frame.

For example, when there are two polar patterns a and b, as shown in [Table 2], two polar patterns are sequentially outputted with one polar pattern in the order a, a until the second frame. When changing from the second frame to the third frame, the b-polar pattern is output instead of the a-polar pattern.

In general, in order to reduce deterioration and afterimage of the liquid crystal, a liquid crystal display uses a POL signal to periodically invert the polarity of the data voltage of the image signal to be output to the panel. The driving method of such a liquid crystal display includes a frame inversion, a column inversion, a line inversion, a dot inversion, and the like. In the conventional general liquid crystal display device using the above driving method, one inversion method is repeated every frame.

However, in the present invention, as described above, two different polar patterns are changed for each preset frame, thereby eliminating an afterimage due to polarity bias generated in the liquid crystal display device to which both the interlaced and FRC methods are applied. The inversion method applied to the present invention may be any one of the above inversion methods.

Here, the jumping period of the polar pattern and the jumping period of the FRC pattern are as described above. That is, when the polar pattern POL PT is changed every 2n frames, the FRC pattern may be jumped every 2n × 2m frames. Here, n is a natural number starting from 1, and m is also a natural number starting from 1.

Third, the present invention forms a plurality of combinations of the FRC pattern and the polar pattern as described above in the direction parallel to the gate line formed on the panel. For example, as shown in FIG. 2, the present invention may operate by separating the FRC pattern and the polar pattern into a first group Group1 and a second group Group2 in the vertical direction of the liquid crystal panel.

However, the number of the group is not necessarily two, and may be variously set in consideration of the size of the panel, the number of gate lines, the number of vertical lines (line) of the FRC pattern, and the like. In the following, for convenience of explanation, the present invention will be described with an example in which the FRC pattern and the polar pattern are set and used in two groups as shown in FIG. 2.

Here, each of the first group and the second group is a combination of the FRC pattern and the polar pattern. That is, in FIG. 2, the first group output in the upper direction of the panel includes FRC patterns jumped every four frames in a C, D, A, B, and D manner, and a, a, b, b, a, a manner. It consists of polar patterns that are jumped every two frames. In addition, the second group is composed of FRC patterns jumped every four frames in the A, C, D, A, B manner, and polar patterns jumped every two frames in the a, b, b, a, a manner. .

For convenience of description, in FIG. 2, the FRC pattern and the polar pattern forming one group are separately shown.

That is, the change of the FRC pattern FRC PT in the first group and the change of the FRC pattern FRC PT in the second group are shown in (Y) of FIG. 2, and the polar pattern POL in the first group. The change of PT) and the change of the polar pattern POL PT in the second group are shown in FIG.

In detail, during the first frame, an image is output by a first group consisting of a C FRC pattern (FRC PT: C) and a polar pattern (POL PT: a) at the top of the panel, and at the bottom of the panel. The image is output by a second group consisting of an A FRC pattern (FRC PT: A) and a polar pattern (POL PT: a).

During the second frame, an image is output by a first group consisting of a D FRC pattern (FRC PT: D) and a polar pattern (POL PT: a) at the top of the panel, and a C FRC pattern ( The image is output by the second group consisting of FRC PT: C) and b polar pattern (POL PT: b).

During the third frame, an image is output by a first group consisting of an A FRC pattern (FRC PT: A) and a b polar pattern (POL PT: b) at the top of the panel, and a D FRC pattern (at the bottom of the panel). The image is output by the second group consisting of FRC PT: D) and b polar pattern (POL PT: b).

During the fourth frame, an image is output by a first group consisting of a B FRC pattern (FRC PT: B) and a b polar pattern (POL PT: b) at the top of the panel, and an A FRC pattern (at the bottom of the panel). The image is output by the second group consisting of FRC PT: A) and a polar pattern (POL PT: a).

During the fifth frame, an image is output by a first group consisting of a D FRC pattern (FRC PT: D) and a polar pattern (POL PT: a) at the top of the panel, and a B FRC pattern (at the bottom of the panel). The image is output by the second group consisting of FRC PT: B) and a polar pattern (POL PT: a).

That is, the FRC pattern (FRC Group1) of the first group is sequentially output from the first frame to the fourth frame in the order of C, D, A, and B, and is jumped in the fifth frame to output the D FRC pattern other than C. do. In addition, the second group FRC pattern (FRC Group2) is sequentially output from the second frame to the fifth frame in the order of C, D, A, B, jumped in the sixth frame not shown, D FRC not C The pattern is output. That is, the FRC pattern of the second group outputs the FRC pattern with a difference of one frame from the first group. In detail, the FRC patterns output in the same frame in two adjacent groups are different from each other.

In addition, a and a are output in the first and second frames of the polar pattern POL Gruop1 of the first group, and b and b are output in the third and fourth frames. In the pattern POL Gruop2, b and b are output in the second and third frames, and a, a, are output in the fourth and fifth frames. That is, the polar pattern of the second group outputs the polar pattern with a difference of one frame from the first group. In detail, the FRC patterns output in the same frame in two adjacent groups may be different from each other, or may be the same.

As described above, the output characteristics of the FRC pattern and the polar pattern in the first group and the second group are shown in [Table 3].

The number of lines in the vertical direction of each of the FRC patterns included in one group may be four.

The reason why the number of lines in the vertical direction of the FRC pattern included in one group is four is that the FRC pattern is generally repeated every four lines in the vertical direction of the panel. Therefore, as the number of lines in the vertical direction of the FRC pattern is changed, the number of lines in the vertical direction of one group may also be changed. In the following, for convenience of explanation, the present invention will be described taking as an example the case where the number of lines in the vertical direction of the FRC pattern is four.

In the configuration as described above, the jumping period of the FRC pattern and the polar pattern in the first group and the jumping period of the FRC pattern and the polar pattern in the second group, as described in the first and second methods, When the pattern POL PT is changed every 2n frames, the FRC pattern is set to jump every 2n x 2m frames. Here, n is a natural number starting from 1, and m is also a natural number starting from 1.

As described above, the reason for forming two or more groups above and below the panel is to reduce the flicker of the panel due to the periodic change of the polar pattern.

That is, if the entire panel is formed in one group, and the FRC pattern and the polar pattern are changed to a constant jumping period, the entire panel may blink every time the polar pattern is changed. However, flickering of the panel can be reduced by forming a plurality of groups above and below the panel and varying the jumping period for each group.

For example, in FIG. 2, when changing from the first frame to the second frame, the polar pattern POL PT of the first group does not change, but the polar pattern POL PT of the second group changes from a to b. do. In addition, when the second frame is changed from the third frame, the polar pattern of the first group changes from a to b, but the polar pattern of the second group does not change. Therefore, the flickering period according to the change of the polarity pattern is increased, so that viewers do not recognize flickering of the panel.

Hereinafter, with reference to FIGS. 3 to 6, a phenomenon in which polarity bias is not generated during a cumulative frame will be described in detail by the liquid crystal display device and the driving method thereof according to the present invention.

3 to 6 are exemplary diagrams for explaining a polarization bias phenomenon during a cumulative frame in the liquid crystal display according to the present invention. FIG. 3 shows the first to fourth frames, and FIG. 4 shows the fifth to fifth frames. An eighth frame is shown, FIG. 5 is a ninth to twelfth frame, and FIG. 6 is a thirteenth to a sixteenth frame.

Hereinafter, the FRC pattern and the polar pattern included in any one of the first group or the second group as described above will be described as an example. That is, although only one group is shown in FIGS. 3 to 6, two or more groups may be formed as shown in FIG. 2.

In addition, for convenience of description, the FRC pattern and the polar pattern shown in FIGS. 3 to 6 are changed and jumped according to the first group shown in FIG. 2 and Table 3. That is, the FRC patterns shown in FIGS. 3 to 6 are C, D, A, B-(jumping)-D, A, B, C-as shown in the first group (Group1) of [Table 3]. (Jumping)-A, B, C, D-Jumping-B, C, D, A are changed in the order, as shown in the first group of Table 3, a, a-jumping-b -b-jumping-a, a-jumping-b, b-jumping-a, a-jumping-b, b-jumping-a, a-jumping-b, b in order.

In addition, in FIG. 3 to FIG. 6, the first line X is input images input to the first to sixteenth frames by the interlaced method, and the second line Y is FRC patterns repeated every four frames. The third line Z represents the polar pattern of the first to sixteenth frames. The fourth line S represents the polarity of the first pixel P1 to the fourth pixel P4 among the pixels of the panel illustrated in FIGS. 3 to 6.

A method of calculating polarity bias at each pixel of the panel is as shown in Equation 4 below. [Equation 4] is the same as [Equation 1] described in the prior art. In the following description, the case in which there is an input image is set to 1, the case in which there is no input image is set to 0, the black is set to 0, the white is set to 1 in the FRC pattern, and the panel polarity is represented. The present invention will be described with (-1) as the case of (-) and (+1) as the case of panel polarity (+).

First, referring to FIG. 3, in the first frame, the first pixel P1 has an input image of 1, an FRC pattern of 0, and a panel polarity of +1. In the first frame, the second pixel P1 has an input image of 1, an FRC pattern of 0, and a panel polarity of -1. In the first frame, the third pixel P3 has an input image of 1, an FRC pattern of 1, and a panel polarity of +1, resulting in an overall polarity value of +1. In the first frame, the fourth pixel P4 has an input image of 1, an FRC pattern of 0, and a panel polarity of -1.

Next, using the calculation method as shown in FIG. 3 and the above, all polarities of the first pixel P1 to the fourth pixel P4 in the second frame are all zero.

3 and the calculation method as described above, in the third frame, in the first frame, the first pixel P1 has an input image of 1, an FRC pattern of 1, and a panel polarity of -1. The polarity value is -1. In the third frame, the second pixel P1 has an input image of 1, an FRC pattern of 0, and a panel polarity of +1. In the third frame, the third pixel P3 has an input image of 1, an FRC pattern of 0, and a panel polarity of -1. In the third frame, since the input pixel is 1, the FRC pattern is 0, and the panel polarity is +1, the fourth pixel P4 has a polarity value of zero.

Next, using the calculation method as shown in FIG. 3 and the above, in the fourth frame, all polarities of the first pixel P1 to the fourth pixel P4 are zero.

Therefore, when the polarities of the first to fourth frames are summed up, the cumulative polarity value of the first pixel P1 is -1, the cumulative polarity value of the second pixel P2 is 0, and the third pixel. The cumulative polarity value of P3 is +1, and the cumulative polarity value of the fourth pixel P4 is zero. That is, polarity skew occurs from the first frame to the fourth frame.

Next, referring to FIG. 4, the cumulative polarity values of the pixels from the fifth frame to the eighth frame are 0, -1, 0, and +1. Polarity bias is also generated during the fifth to eighth frames.

Next, referring to FIG. 5, cumulative polarity values of the pixels from the ninth to twelfth frames are +1, 0, -1, and 0. FIG. Polarity bias is also generated during the ninth to twelfth frames.

Next, referring to FIG. 6, the cumulative polarity values of the pixels from the thirteenth frame to the sixteenth frame are 0, +1, 0, and −1.

Finally, the cumulative polarity values of the pixels of the first to sixteenth frames are calculated as follows.

The cumulative value of the first pixel P1 is 0 (= (-1) (first to fourth frames) + (0) (five to eighth frames) + (+1) (ninth to nineth frames). 12 frames) + (0) (13 th frame to 16 th frame).

The cumulative value of the second pixel P2 is 0 (= (0) (first to fourth frames) + (-1) (five to eighth frames) + (0) (ninth to twelfth frames). Frame) + (+ 1) (13 th frame to 16 th frame).

The cumulative value of the third pixel P3 is 0 (= (+ 1) (first to fourth frames) + (0) (fiveth to eighth frames) + (-1) (ninth to nineth frames). 12 frames) + (0) (13 th frame to 16 th frame).

The cumulative value of the fourth pixel P4 is 0 (= (0) (first to fourth frames) + (+1) (fiveth to eighth frames) + (0) (ninth to twelfth frames). Frame) + (-1) (13 th frame to 16 th frame).

That is, in the embodiment of the present invention as described above, each pixel has polarity skew every four frames, but the total accumulated polarity value for 16 frames is zero, so that no polarity skew occurs.

Therefore, in the present invention, the polar pattern and the FRC pattern are superimposed as described above, while the polar pattern and the FRC pattern are jumped and applied at predetermined intervals, thereby reducing the total cumulative polarity value for 16 frames to zero. I can make it. For this reason, the present invention does not generate polarity bias in the liquid crystal display device to which both the interlaced method and the FRC method are applied.

In addition, the present invention, as described above, by forming two or more groups in the vertical direction, by changing the conversion order of the FRC pattern and the polar pattern for each group, it is possible to prevent the flicker of the panel.

That is, the present invention can prevent afterimages due to polarity bias in a liquid crystal display device to which an interlaced method and an FRC method are applied by a polar pattern, an FRC pattern, and a method of forming at least two groups.

The jumping scheme described above with reference to FIGS. 3 to 6 is shown in Table 4 below.

That is, the present invention shown in FIGS. 3 to 6 and Table 4 is a method of jumping a polar pattern (panel polarity) every two frames and jumping the FRC pattern every four frames.

On the other hand, an object of the present invention to prevent afterimages due to polarity bias, in addition to the method of jumping the polar pattern and the FRC pattern, as described above, in the holding method as shown in Table 5 below Can also be achieved.

That is, according to the present invention, as shown in Table 5, the FRC pattern may be held every four frames, and the polar pattern (panel polarity) may be held every two frames. In detail, the present invention shown in Table 5 may hold the FRC pattern output in the fourth frame and continuously output the fifth frame. In this case, in the sixth frame, the next pattern of the FRC pattern output in the fifth frame is sequentially output.

At this time, the polar pattern (panel polarity) is output in the same order as in the jumping method.

In addition, the method of holding the FRC pattern and the polar pattern may also be configured by at least two groups.

That is, the present invention applies the interlaced method and the FRC method by variously applying a method of applying a polar pattern, a method of applying an FRC pattern, a method of forming at least two or more groups, and a jumping method or a holding method. It is possible to prevent afterimages due to polarity bias in the liquid crystal display device.

In the following, the present invention using the jumping method is described for convenience of explanation. However, the following description is also applicable to the present invention using the holding method.

7 is a configuration diagram of one embodiment of an afterimage removing apparatus applied to a liquid crystal display according to the present invention, FIG. 8 is a configuration diagram of an embodiment of a liquid crystal display according to the present invention, and FIG. 9 is a liquid crystal according to the present invention. FIG. 10 is a configuration diagram of a data driver applied to a display device, and FIG. 10 is a flowchart illustrating a method of driving a liquid crystal display device according to the present invention.

As shown in FIG. 7, the afterimage removing apparatus 500 applied to the liquid crystal display according to the present invention includes a receiver 410, a selector 420, a general mode driver 430, and an afterimage removal mode driver 440. And a transmitter 450.

The receiver 410 receives an input image RGB of the input data and timing signals from an external system. The timing signals include a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal Data Enable, DE, a main clock CLK, and the like. The receiver 410 samples the input image RGB of the input data at the main clock CLK timing, and synchronizes the input image RGB with an external timing signal.

The selector 420 transmits the input image and the timing signal to the normal mode driver 430 or to the afterimage removal mode driver 440 in response to a mode selection signal MS input from the outside. Determine whether or not to do so.

The normal mode driver 430 is selected and driven by the selection unit 420 when a general input image other than an interlace input image is input from an external system. That is, the normal mode driver 430 is driven when an input image not using the interlaced method as described above is input to control the gate driver 200 and the data driver 300 shown in FIG. 8. The gate control signal GCS and the data control signal DCS are generated, and the input image RGB is aligned to output the aligned image data RGB. That is, the general mode driver 430 is the same as the configuration used to generate a control signal or to sort data in a general timing controller, and arranges the control signal generator 431 and the input image to generate the control signal. And a data alignment unit 432 for outputting the aligned image data RGB. Therefore, detailed description thereof will be omitted.

The afterimage removal mode driver 440 is selected by the selection unit 420 when an input image (hereinafter, simply referred to as an “interlaced input image”) to be output by an interlaced method is input from an external system. Driven. The afterimage removal mode driver 440 may input information on the cumulative frame, the jumping period of the FRC pattern, the jumping period of the polar pattern, the FRC patterns, and the group information described in FIGS. 2 to 6. Can be. However, such information may be input from a memory outside the afterimage removing apparatus 500, may be input from a memory inside the afterimage removing apparatus 500, and may be stored in the afterimage removing mode driving unit 440. It may be.

The afterimage removal mode driver 440 may include a counter 441 for counting frames, an afterimage removal control signal generator 442 for generating an afterimage removal control signal according to a count value generated from the counter, and the And a residual image removing data alignment unit 443 for generating the image data according to the count value generated from the counter.

The counter 441 counts a frame period using any one of the vertical synchronization signal Vsync, the horizontal synchronization signal Hsync, and the data enable signal Data Enable (DE).

The afterimage removal control signal generator 442 generates a gate control signal GCS for driving the gate driver 200 according to the count value, and data for driving the data driver 300. Generate a control signal DCS. In particular, the data control signal DCS includes a pole POL for allowing the data driver 300 to output image signals corresponding to the polar pattern POL PT described with reference to FIGS. 3 to 6. ) Signal is included.

For example, the afterimage removal control signal generator 442 generates a POL signal for causing the data driver 300 to change the polarity of the image signal output to each pixel every two frames. .

The afterimage removing data alignment unit 443 may select FRC patterns FRC PT A to FRC PT D using the count value, the FRC pattern jumping period, and group information, and then, for each frame, the data driver 300. Generates and outputs image data to be transmitted.

That is, the afterimage removing data alignment unit 443 generates the image data RGB to be output during one frame by using the input image and the FRC patterns shown in FIGS. 3 to 6, and then the image data. (RGB) is transmitted to the data driver 300.

The transmitter 450 transmits various control signals DCS and GCS generated from the normal mode driver 430 or the afterimage removal mode driver 440 to the gate driver 200, and the general mode driver 430 or the image data RGB generated from the afterimage removal mode driver 440 is transmitted to the data driver 300.

The afterimage removing apparatus 500 as described above may be configured separately from the timing controller on the main board of the liquid crystal display according to the present invention. As illustrated in FIG. 8, the afterimage removing apparatus 500 may be connected to the timing controller 400 of the liquid crystal display. It can be built in.

That is, as shown in FIG. 8, the liquid crystal display according to the present invention includes a panel 100, a timing controller 400, a data driver 300, and a gate driver 200. 500 may be included in the timing controller 400.

First, the panel 100 includes a thin film transistor TFT and pixels including pixel electrodes, which are formed at respective regions defined by intersections of the gate lines and the data lines DL1 to DLm.

The thin film transistor TFT supplies a video signal transmitted from the data line to the pixel electrode in response to a scan signal from the gate lines GL1 to GLn. The pixel electrode adjusts the transmittance of light by driving a liquid crystal positioned between the pixel electrode and the common electrode in response to the video signal.

The liquid crystal mode of the panel applicable to the present invention may be any mode of liquid crystal mode as well as a TN mode, a VA mode, an IPS mode, and an FFS mode. Further, the liquid crystal display device according to the present invention can be implemented in any form such as a transmissive liquid crystal display device, a transflective liquid crystal display device, and a reflective liquid crystal display device.

Next, the afterimage removing apparatus 500 is configured as shown in FIG. 7, and removes the polarity bias phenomenon of the panel by using the principle as described with reference to FIGS. 3 to 6. The afterimage removal apparatus 500 may be included in the timing controller 400.

Next, the timing controller 400 uses the timing signals input from the external system, that is, the vertical synchronization signal Vsync, the horizontal synchronization signal Hsync, and the data enable signal DE, And a data control signal DCS for controlling the operation timing of the data driver 300 and generates digital image data RGB to be transmitted to the data driver 300 ). That is, the timing controller 400 may be formed separately from the afterimage removing apparatus 500 to output control signals and image data required in the general mode, and when the afterimage removing apparatus 500 is built in, In addition, all of the functions of the afterimage removing apparatus 500 may be performed.

Next, the gate driver 200 supplies a scan signal to the gate lines by using the gate control signals GCS generated by the timing controller 400 or the afterimage removing apparatus 500. The gate driver 200 may include at least one gate drive IC. The gate driver 200 applied to the present invention may be applied to a conventional liquid crystal display. Meanwhile, the gate driver 200 according to the present invention may be formed independently of the panel 100 and may be electrically connected to the panel in various ways. However, the gate driver 200 may be mounted in the panel Or a gate-in-panel (GIP) method.

Next, the data driver 300 includes at least one source drive IC. The data driver 300 converts the digital image data RGB transmitted from the timing controller 400 into an analog video signal and supplies the analog video signal to the gate line And supplies a video signal to the data lines.

That is, the data driver 300 converts the digital image data into the analog image signal and outputs the converted data to the data line using gamma voltages supplied from a gamma voltage generator (not shown). To this end, each of the source drive ICs constituting the data driver 300 includes a shift register unit 331, a latch unit 332, a digital-to-analog converter (DAC) 333, and the like, as shown in FIG. 9. An output buffer 334 is included.

The shift register unit 331 generates a sampling signal using the signals received from the afterimage removing apparatus 500 or the timing controller 400.

The latch unit 332 latches the image data received from the afterimage removing apparatus 500 or the timing controller 400 and simultaneously outputs the image data to the digital-to-analog converter 333 (DAC). do.

The digital-to-analog converter 330 simultaneously converts the image data transmitted from the latch unit 332 into a positive or negative data voltage and outputs the same. That is, the digital analog converter 330 converts the image data into positive or negative analog data voltages (video signals) by using the POL signal transmitted from the afterimage removing device 400. To print.

For example, the digital-to-analog converter (DAC) 330 may output the image signals (data voltages) output to the panel in the first and second frames according to the POL signal (Z) of FIG. 3. A) polarity pattern (POL PT: a) as shown in Fig. 3). In the third and fourth frames, the image signals (data voltages) output to the panel are as shown in (Z) of FIG. b It should have a polar pattern (POL PT: b).

The output buffer 340 outputs the positive or negative data voltage transmitted from the digital-to-analog converter 330 to the data lines of the panel 100.

That is, when the interlaced input image driven in an interlaced manner is received from an external system, the liquid crystal display according to the present invention transmits the image data including the FRC pattern to the data driver 300 to the data driver 300. A POL signal for controlling the polarity of the image signal to be output from the data driver 300 is generated and transmitted to the data driver 300.

In this case, the liquid crystal display according to the present invention generates the image data to which the FRC pattern (FRC PT) is added by the method as shown in FIGS. 3 to 6, and the polarity as shown in FIGS. 3 to 6. A POL signal capable of outputting a pattern POL PT is generated and transmitted to the data driver 300.

The data driver 300 receives the image data RGB including the FRC pattern from the timing controller 400 or the afterimage removing device 500, and converts the received digital image data into an analog image signal. Output to the data line of the panel. At this time, the data driver 300 changes the polarity of the video signal according to the POL signal and outputs the changed polarity.

The configuration of the liquid crystal display device according to the present invention described above is summarized as follows.

That is, in the liquid crystal display according to the present invention, when the interlaced input image is received from the panel 100 on which the gate lines and the data lines are formed, an external system receives the FRC pattern to be added to the input image, and the input image. An afterimage removal device 500 and the afterimage removal device 500 for generating at least two groups formed in parallel with the gate lines during one frame by generating a polar pattern to be output. And a data driver 300 for converting the image data inputted from the signal into a data voltage and inverting the polarity of the data voltage based on the polar pattern and outputting the data data to the data lines.

The afterimage removing apparatus 500 converts the input image based on the FRC pattern to generate the image data, and then transmits the image data to the data driver 300, corresponding to the polar pattern. A POL signal is generated and transmitted to the data driver 300.

In addition, the afterimage removing apparatus 500 generates the image data by jumping the plurality of FRC patterns to be included in the one group for each predetermined frame, and then transmits the image data to the data driver 300. The POL signal is generated and transmitted to the data driver so that the plurality of polar patterns to be included in the one group can be jumped every other predetermined frame.

Herein, when the polar pattern POL PT is jumped every 2n frames, the FRC pattern is changed every 2n × 2m frames, and n and m are natural numbers greater than one.

In addition, when there are two or more groups, the periods for jumping the FRC pattern and the polar pattern for each group are the same, and the FRC patterns output through groups adjacent to each other during one frame may be different.

In addition, as described with reference to FIGS. 3 to 6, the FRC patterns included in the one group are four, the polar patterns are two, the FRC patterns are jumped every four frames, and the polar pattern If they are jumped every two frames, the cumulative polarity value of the pixels formed in the panel is zero every 16 frames.

The driving method of the liquid crystal display according to the present invention as described above will be described with reference to FIG.

In the first process, when an interlace input image is received from an external system, the afterimage removing apparatus 500 generates an FRC pattern to be added to the input image and a polar pattern to output the input image to form a group. Generating at least two groups to be output during one frame, converting the input image based on the FRC pattern, generating the image data, and generating a POL signal corresponding to the polar pattern; The image data and the poll signal are transmitted to the data driver 300 (S902 to S908).

The first process may again be subdivided as shown in FIG. 10.

First, the afterimage removing apparatus 500 determines whether an interlace input image is input from an external system (S902). This function is achieved by the selection unit 420 receiving the mode selection signal MS. That is, the external system should inform the liquid crystal display using the mode selection signal MS to determine whether to perform a de-interlace operation. In response to the determination result (S902), when the general input image other than the interlace input image is received, the afterimage removing apparatus 500 generates the image data by a general method and then sends the generated image data to the data driver 300. send.

Next, the afterimage removing apparatus 500 defines a counter operation and a maximum value for generating an FRC operation and a poll (POL) (S904).

That is, the counter 441 may jump or hold a value that is counted at every externally set period, so that the afterimage removing control signal generator 442 or the afterimage removing data is aligned. The unit 443 may select an FRC pattern and a polar pattern POL to be output for each frame.

Next, the afterimage removing apparatus 500 counts frames and lines for the FRC operation and the generation of the poll (POL) (S906). That is, the afterimage removing apparatus 500 counts frames for jumping the FRC pattern or the polar pattern, and counts the lines to form the polar patterns in groups for each line of the panel.

Finally, the afterimage removing apparatus 500 generates the FRC pattern and the polar pattern by using the frame count value and the line count value.

In the second process, the data driver 300 receives the image data from the afterimage removing apparatus, changes the received digital image data into an analog data voltage, and changes the polarity of the data voltage according to the pole signal. The data is converted and output to the data line of the panel (S910). The analog image data transmitted to the data driver may be transmitted from the afterimage removal data aligner 443, or may be transmitted from the data aligner 432 of the normal mode driver 430.

Meanwhile, in the first process, generating the image data and the POL signal and transmitting the generated image data and the POL signal to the data driver, the afterimage removing apparatus 500 may include a plurality of FRC patterns to be included in the one group. After generating the image data by jumping every predetermined frame, and transmitting the image data to the data driver, and the afterimage removing apparatus 500, the plurality of polar patterns to be included in the one group, The method may include generating a POL signal to be jumped at every other preset frame and transmitting the generated POL signal to the data driver.

That is, the present invention as described above is to group the polar pattern and the FRC pattern, the groups are grouped in the same size (size) based on the displayed image (display).

Here, each group may be set to any number of lines 1 to N in one frame. That is, the number of lines in the group may change according to the change in the number of vertical lines that may vary the FRC pattern.

FIG. 11 is a flow chart illustrating still another embodiment of a method of driving a liquid crystal display device according to the present invention. FIG. Exemplary diagrams illustrating positions of representative pixels selected in a panel applied to a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 14 illustrates a method of calculating polarity values of representative pixels in a method of driving a liquid crystal display according to the present invention. FIG. 15 is an exemplary diagram illustrating a range of threshold values applied to a liquid crystal display driving method according to the present invention.

In the method of driving the liquid crystal display according to the present invention described above, as described with reference to FIG. 10, first, the afterimage removing apparatus 500 determines whether an interlace input image is received from an external system ( S902) Second, when the interlace input image is received, the afterimage removing apparatus 500 generates an FRC pattern to be added to the input image and a polar pattern to output the input image to form one group, Generating at least two groups to be output during a frame, converting the input image based on the FRC pattern, generating the image data, and generating a POL signal corresponding to the polar pattern; If the image data and the poll signal are transmitted to the data driver 300 (S904 to S908), and third, if the interlaced input image is not received, the image data may be sent by a general method. Generate image data, and transmit the image data to the data driver 300 (S912). Fourth, the data driver 300 receives the image data from the afterimage removing apparatus 500 and receives the image data. The digital image data is changed to an analog data voltage, and the polarity of the data voltage is converted according to the pole signal and output to the data line of the panel (S910).

In this case, as described with reference to FIG. 7, when the mode selection signal MS is transmitted from the external system, the selector 420 determines that an interlaced input image is received and removes afterimages. If the mode selection signal MS is not transmitted from the external system, a progressive input image (hereinafter, simply referred to as a 'progressive input image') is received. In response to the determination, the video data is generated in a general manner.

However, even when a progressive input image is received, an afterimage may occur due to polarity bias as described above.

Accordingly, in order to remove both the afterimage due to the polarity bias of the interlaced input image and the afterimage due to the polarity bias of the progressive input image, another embodiment of the method of driving the liquid crystal display according to the present invention is illustrated in FIG. 11. The same method is used.

First, before explaining another embodiment of the liquid crystal display driving method according to the present invention, to implement another embodiment of the liquid crystal display driving method according to the present invention, the afterimage The removal device 500 is described with reference to FIG. 12.

As shown in FIG. 12, the afterimage removing apparatus 500 applied to the liquid crystal display driving method according to the present invention includes a receiver 410, a selector 420, and a normal mode driver 430. ), The afterimage removal mode driver 440 and the transmitter 450.

First, the receiver 410 receives an input image RGB and timing signals from an external system. The timing signals include a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal Data Enable, DE, a main clock CLK, and the like. Here, the input image may be an interlaced input image or may be a progressive input image.

Next, as illustrated in FIG. 11, the selector 420 calculates a polarity value of the representative pixel selected as the representative pixel (S104), and when the calculated value calculated through the process is larger than a preset threshold. In operation S106, the input image is transmitted to the afterimage removal mode driver 440. When the calculated value is smaller than the threshold value, the input image is transmitted to the normal mode driver 430.

That is, the afterimage removing apparatus 500 illustrated in FIG. 7 transmits the input image and the timing signal to the normal mode driver 430 in response to the mode selection signal MS input from the outside. It is determined whether to transmit to the afterimage removal mode driver 440. However, the afterimage removing apparatus 500 illustrated in FIG. 12 transmits the input image to the afterimage removing mode driver 440 through the selection unit 420 or to the normal mode driver 430. It is up to you to decide whether or not to transmit.

Therefore, the afterimage removal apparatus 500 including the selector 420 does not need to be provided with a separate transmission line to receive the mode selection signal MS from the external system. Accordingly, in the liquid crystal display according to the present invention, a function for transmitting and receiving the mode selection signal MS may be omitted, and when the afterimage removing apparatus 500 is configured as an integrated circuit, the mode selection signal The pin for transmitting and receiving the MS may be omitted.

Next, the normal mode driver 430 is selected and driven by the selection unit 420 when an input image causing an afterimage caused by polarity bias is input through the receiver 410 from an external system. . That is, the normal mode driver 430 is driven when an input image not using the interlaced method as described above is input to control the gate driver 200 and the data driver 300 shown in FIG. 8. The gate control signal GCS and the data control signal DCS are generated, and the input image RGB is aligned to output the aligned image data RGB.

That is, the general mode driver 430 is the same as the configuration used to generate a control signal or to sort data in a general timing controller, and arranges the control signal generator 431 and the input image to generate the control signal. And a data alignment unit 432 for outputting the aligned image data RGB. Therefore, detailed description thereof will be omitted.

Next, the afterimage removal mode driver 440 is selected and driven by the selection unit 420 when an input image causing an afterimage due to polarity bias is input through the receiver 410 from an external system. do. The afterimage removal mode driver 440 may input information on the cumulative frame, the jumping period of the FRC pattern, the jumping period of the polar pattern, the FRC patterns, and the group information described in FIGS. 2 to 6. Can be. However, such information may be input from a memory outside the afterimage removing apparatus 500, may be input from a memory inside the afterimage removing apparatus 500, and may be stored in the afterimage removing mode driving unit 440. It may be.

The afterimage removal mode driver 440 may include a counter 441 for counting frames, an afterimage removal control signal generator 442 for generating an afterimage removal control signal according to a count value generated from the counter, and the And a residual image removing data alignment unit 443 for generating the image data according to the count value generated from the counter.

The counter 441, the control signal generator 442, and the afterimage removal data aligning unit 430 may be configured by the counter 441 and the control signal generator 442 of FIG. 7. And the same as the configuration and function of the afterimage removal data alignment unit 430, a detailed description thereof will be omitted.

Finally, the transmitter 450 transmits various control signals DCS and GCS generated from the normal mode driver 430 or the afterimage removal mode driver 440 to the gate driver 200. The image driver RGB of the mode driver 430 or the afterimage removal mode driver 440 is transmitted to the data driver 300.

The afterimage removing apparatus 500 as described above may be configured separately from the timing controller on the main board of the liquid crystal display according to the present invention. As illustrated in FIG. 8, the afterimage removing apparatus 500 may be connected to the timing controller 400 of the liquid crystal display. It can be built in.

On the other hand, in the above, the selection unit 420 analyzes the input image received through the receiver 410, and transmits the input image to the afterimage removal mode driver 440, or the normal mode driver 430 The present invention has been described with an example of judging whether or not to transmit to the network.

However, the selector 420 may be provided between the normal mode driver 430 and the afterimage removal mode driver 440.

In this case, the selector 420 analyzes the input image output from the normal mode driver 430, and if it is determined that the input image causes an afterimage caused by polarity bias, the input image is removed in the afterimage removal mode. If it is determined that the input image is not causing an afterimage caused by polarity bias, the input image may be transmitted to the transmitter 440.

That is, the selector 420 analyzes the input image received from the external system and transmits the input image to the general mode driver 430 or to the afterimage removal mode driver 440. Can be determined. In addition, the selector 420 is received from the external system and the general mode driver 430 analyzes an input image of a state in which the color, luminance, etc. are primarily changed, and the afterimage removal mode driver 440 is used. It may be determined whether to transmit to or through the transmitter 450.

Hereinafter, for convenience of description, the present invention will be described with an example in which the selector 420 receives the input image from the receiver 420 as shown in FIG. 12.

Second, another embodiment of a method of driving a liquid crystal display according to the present invention will be described with reference to FIG. 11.

First, information about the representative pixel is stored in the selection unit 420 or the memory inside the afterimage removing apparatus 500 or the memory outside the afterimage removing apparatus 500 (S102).

The representative pixel is a pixel analyzed to determine polarity bias of the input image, and may be variously set and stored by the manufacturer of the liquid crystal display according to the present invention.

For example, as shown in FIG. 13, the representative pixel includes four pixels positioned at left and right corners of the upper and lower portions of the panel 100, and one pixel positioned at the center of the panel 100. It may include.

The larger the number of the representative pixels, the more accurately the polarity bias of the input image can be determined. However, as the number of the representative pixels increases, the capacity of the memory and the workload of the selector 420 may increase. Therefore, the number of the representative pixel may be set to an appropriate number in consideration of the above factors. Hereinafter, the present invention will be described with an example in which the number of the representative pixels is five, as shown in FIG.

Next, when the input image is received, the selector 420 calculates a polarity value of each of the representative pixels (S104).

A method of calculating the polarity value will now be described with reference to FIG. 14.

For example, the input image X corresponding to the representative pixel A among the representative pixels is white (W, 255 gray) in the first frame 1Frame and black (B, 0) in the second frame 2Frame. Gray), white (W, 255 gray) in the third frame (3 Frame), and black (B, 0 gray) in the fourth frame (4 Frame). In addition, the panel is driven in a one-frame inversion manner so that the panel polarity (inversion polarity) Y of the panel is + in the first frame,-in the second frame, + in the third frame, and Assume-in 4 frames. When the panel polarity is +, the panel polarity is 1, and when the panel polarity is-, the panel polarity is -1.

In this case, the polarity values Z for each frame of the representative pixel A are +255, 0, +255, and 0 during the first to fourth frames, and thus, the polarity values of the representative pixel A ( K) becomes +510.

That is, the polarity value Z for each frame is a value obtained by multiplying the gray of the input image X by the panel polarity, and is +255 (= 255 x 1) in the first frame and 0 (in the second frame). = 0 x (-1)), +255 (= 255 x 1) in the third frame, and 0 (= 0 x (-1)) in the fourth frame. Therefore, the polarity value K of the representative pixel A becomes +510 (= 255 + 0 + 255 + 0).

When the polarity value K of the representative pixel B is calculated using the method described above, the polarity value K of the representative pixel B becomes 0 (= 255 + 0 + (-255) + 0).

When the polarity value K of the representative pixel C is calculated using the method described above, the polarity value K of the representative pixel C is +60 (= 110 + (-130) + 150 + (- 70).

Herein, the input image for each frame corresponding to the representative pixel C is not white or black, but may be 110, 130, 150, and 70 gray.

Next, the selector 420 determines whether the polarity values K calculated in the process S104 exceed a preset threshold value, and if the polarity values exceed the threshold value, determines that the polarity values are greater than the threshold value. When the input image is transmitted to the afterimage removal mode driver 440, and the polarity values are determined to be smaller than the threshold value, the input image is transmitted to the normal mode driver 430 (S106).

For example, when the threshold is 100, the polarity value K of the representative pixels A, B, C, D, and E is the same polarity value K as that of the representative pixel A, that is, 150. If, the polarity value K of each of the representative pixels exceeds the threshold. In this case, the selector 420 determines that the input image may cause an afterimage caused by polarity bias, and transmits the input image to the afterimage removal mode driver 440.

As another example, when the threshold is 100, the polarity value K of the representative pixels A, B, C, D, and E is the same polarity value K as the representative pixel B, that is, 0. If, the polarity value K of each of the representative pixels is smaller than the threshold. In this case, the selector 420 determines that the input image does not cause an afterimage due to polarity bias, and transmits the input image to the general mode driver 430.

As another example, when the threshold is 100 and each of the polarity values K of the representative pixels A, B, C, D, and E is 60, 90, 120, 130, 140, the representative The polarity values 60 and 90 of the pixel A and the representative pixel B are smaller than the threshold, and the polarity values 120, 130 and 140 of the representative pixel C, the representative pixel D, and the representative pixel E are larger than the threshold.

In this case, since the polarity values of all the representative pixels did not exceed the threshold value, the selector 420 determines that the input image does not cause an afterimage caused by polarity bias, and thus displays the input image. The mode driver 430 may transmit the data.

However, since the polarity values 120, 130, and 140 of the majority of the representative pixels (the representative pixel C, the representative pixel D, and the representative pixel E) exceed the threshold, the selector 420 may not display the input image. The image may be transmitted to the afterimage removal mode driver 440 by determining that an afterimage may be caused by polarity bias.

That is, the selector 420 may determine that the input image causes an afterimage due to polarity bias only when the polarity values of all the representative pixels exceed the threshold value. When the polarity value of the representative pixels of the set number or more exceeds the threshold, it may be determined that the input image causes an afterimage caused by polarity bias.

In this case, as shown in FIG. 15, when the maximum value Max of the polarity value K is 150%, the threshold value may be set to a value corresponding to N%.

Accordingly, when the polarity value of the representative pixels exceeds a threshold corresponding to N%, the selector 420 may determine that the input image causes an afterimage caused by polarity bias.

After the determination determines that the input image causes an afterimage caused by polarity bias, the selection unit 420 continuously performs the processes S104 and S106 so that the input image is subjected to polarity bias. It is determined whether or not to cause an afterimage.

In this case, the selection unit 420 may perform the determination using a threshold value different from the threshold value set above.

That is, the selector 420 may determine whether the input image causes an afterimage due to polarity bias, using a threshold value corresponding to N%.

In addition, when it is determined that the input image is causing an afterimage due to polarity bias, using the threshold value corresponding to N%, the polarity value is transmitted when the input image is transmitted to the afterimage removal mode driving unit 440. When the maximum value (K) of (K) is set to 100%, a value corresponding to M% is set as the threshold value, and it is possible to determine whether or not the input image is causing an afterimage due to polarity bias. have. Here, the threshold corresponding to M% may be smaller than the threshold corresponding to N%, as shown in FIG. 15.

As described above, in the state where the threshold (N%) which is a reference for the determination for transmitting the input image to the afterimage removal mode driver 440 and the input image are being transmitted to the afterimage removal mode driver 440. The threshold value (M%), which is a reference for determining whether to continuously transmit the input image to the afterimage removal mode driver 440 or to transmit the input image to the normal mode driver 430, is different. The reason for setting is to prevent the driving of the two driving units 430 and 440 from changing at any one threshold.

That is, in the state in which the threshold for transmitting the input image to the afterimage removal mode driver 440 and the input image are being transmitted to the afterimage removal mode driver 440, the normal mode driver 430 is used. If the thresholds to be transmitted to the same) are the same, and when the polarity value K changes only slightly with respect to the one threshold, the selector 420 drives the two drivers 430 and 440. Should be replaced from time to time.

However, as shown in FIG. 15, a threshold value (N%) for transmitting the input image to the afterimage removal mode driver 440 and a state in which the input image is being transmitted to the afterimage removal mode driver 440. If the threshold value (M%) for transmitting the input image to the normal mode driver 430 is spaced apart with a predetermined gap, while the input image is being transmitted to the afterimage removing mode driver 440, Even if the polarity value K is changed between the two threshold values, the selector 420 may continuously transmit the input image to the afterimage removal mode driver 440.

In addition, even while the polarity value K is changed between the two threshold values while the input image is being transmitted to the normal mode driver 430, the selector 420 continuously displays the input image. It may be transmitted to the normal mode driver 430.

That is, since the driving of the afterimage removal mode driver 440 and the normal mode driver 430 may be controlled using two threshold values, the afterimage removal mode driver 440 and the normal mode driver 430 may be controlled. Can be driven more stably.

Next, the afterimage removal mode driving unit 440 which has received the input image from the selection unit 420 uses the processes S904 to S906 described with reference to FIG. 10 to correct the polarity of the input image. The input image is converted to output the converted image data so that the afterimage caused by the image may be removed. The image data is transmitted to the data driver 300 through the transmitter 450.

Next, the normal mode driver 430 receiving the input image from the selector 420 may process the input image using the process S912 described with reference to FIG. 10 (S110). . That is, the general mode driver 430 converts the input image into image data using a general method. The image data is transmitted to the data driver 300 through the transmitter 450.

Finally, the data driver 300 receives the image data from the afterimage removing apparatus 500, changes the received digital image data into an analog data voltage, and changes the polarity of the data voltage according to the pole signal. The data is converted and output to the data line of the panel 100 (S112). The process S112 is the same as the last process described with reference to FIG. 10, that is, the image signal output process S910.

Here, the analog image data transmitted to the data driver 300 may be transmitted from the afterimage removal data aligning unit 443 of the afterimage removal mode driver 440, and the image of the normal mode driver 430 may be transmitted. The data may be transmitted from the data aligning unit 432.

On the other hand, in the above description, when the input image causes an afterimage caused by polarity bias, the present invention has been described by using the afterimage removal method described with reference to FIG. 10, but the present invention is not limited thereto. .

That is, when the input image causes an afterimage caused by polarity bias, the afterimage removing apparatus 500 may remove the afterimage of the input image using various methods currently used.

It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

100: panel 200: gate driver
300: Data driver 400: Timing controller
500: afterimage removal device 410: receiving unit
420: selection unit 430: normal mode drive unit
440: Afterimage removal mode driver 450: Transmitter

Claims (19)

A panel on which gate lines and data lines are formed;
When an interlaced input image is received from an external system, an FRC pattern to be added to the input image and a polar pattern for outputting the input image are generated and formed as a group, and formed in parallel with the gate lines during one frame. Afterimage removal apparatus for generating at least two or more of the groups; And
And a data driver for converting image data input from the afterimage removing device into a data voltage and inverting the polarity of the data voltage based on the polar pattern and outputting the data data to the data lines. The method according to claim 1,
The afterimage removal device,
After converting the input image based on the FRC pattern to generate the image data, and transmits the image data to the data driver,
And generating a POL signal corresponding to the polar pattern and transmitting the POL signal to the data driver. The method according to claim 1,
The afterimage removal device,
After generating the image data by jumping or holding a plurality of the FRC pattern to be included in the one group for each predetermined frame, and transmits the image data to the data driver,
And generating and transmitting a POL signal to the data driver so that the plurality of polar patterns to be included in the one group can be jumped or held for every other predetermined frame. The method of claim 3, wherein
And when the polar pattern POL PT is jumped or held every 2n frames, the FRC pattern is changed every 2n × 2m frames, and n and m are natural numbers greater than one. The method of claim 3, wherein
If there are two or more groups,
The periods of jumping or holding the FRC pattern and the polar pattern for each group are the same, and the FRC patterns output through groups adjacent to each other during one frame are different from each other. The method according to claim 1,
And the number of lines of the FRC pattern to be included in the one group is four. The method according to claim 1,
When the FRC patterns included in the group are four, the polar patterns are two, the FRC patterns are jumped or held every four frames, and the polar patterns are jumped or held every two frames.
The cumulative polarity value of the pixels formed in the panel is zero every 16 frames. When the interlaced input image is received from an external system, the afterimage removing device generates an FRC pattern to be added to the input image and a polar pattern to output the input image to form a group, and the group to be output during one frame. Generating at least two;
The afterimage removing apparatus converts the input image based on the FRC pattern to generate the image data, and generates a POL signal corresponding to the polar pattern to generate the image data and the pole signal. Transmitting to a driver; And
And changing, by the data driver, the image data to a data voltage, and converting the polarity of the data voltage according to the pole signal and outputting the polarity of the data voltage to a gate line of the panel. The method of claim 8,
Generating and transmitting the image data and the POL signal to the data driver,
Generating, by the afterimage removing apparatus, the image data by jumping or holding the plurality of FRC patterns to be included in the one group for each predetermined frame, and then transmitting the image data to the data driver; And
And generating, by the image removing apparatus, a POL signal to be transmitted to the data driver so that the plurality of polar patterns to be included in the one group can be jumped or held for each other predetermined frame. Display device driving method. The method of claim 9,
When the polar pattern POL PT included in each group is jumped or held every 2n frames, the FRC pattern included in each group is changed every 2n x 2m frames, and n and m are 1 A method of driving a liquid crystal display device, which is a larger natural number. A panel on which gate lines and data lines are formed;
Receiving a progressive input image or an interlaced input image and determining whether the input image causes an afterimage caused by polarity bias, and when determining that the afterimage is caused by polarity bias, An afterimage removing device for converting the input image so as not to cause the image and outputting the converted image data; And
And a data driver for converting the image data input from the afterimage removing device into a data voltage and inverting the polarity of the data voltage based on the polar pattern and outputting the data data to the data lines. The method of claim 11,
The afterimage removal device,
Calculating a polarity value of the input image corresponding to the representative pixel selected as the representative pixel among the input images;
When the calculated calculated value is larger than a preset threshold, the image data is generated by converting the input image so that an afterimage caused by the input image can be removed.
And when the calculated value is smaller than the threshold, realign the input image according to the panel and output the rearranged image data. The method of claim 11,
The afterimage removal device,
Generating at least two FRC patterns to be added to the input image and a polar pattern to output the input image to form one group, and forming at least two groups formed in parallel with the gate lines during one frame; A residual image removal mode driver configured to generate the image data by jumping a plurality of the FRC patterns to be included in the one group for each predetermined frame;
A normal mode driver for rearranging the input image to fit the panel and generating the rearranged image data;
The polarity value of the input image corresponding to the representative pixel selected as the representative pixel among the input images is calculated. When the calculated value is larger than a preset threshold, the input image is transmitted to the afterimage removing mode driver. A selection unit for transmitting the input image to the normal mode driver when the calculated value is smaller than the threshold value; And
And a transmitter configured to transmit the image data output from the afterimage removal mode driver or the image data output from the normal mode driver to the data driver. 14. The method of claim 13,
The afterimage removal device,
Determining whether to transmit the input image to the afterimage removal mode driver by using a first threshold value,
And in the state where the input image is being transmitted to the afterimage removal mode driver, determining whether to transmit the input image to the normal mode driver by using a second threshold value. 15. The method of claim 14,
At least two representative pixels,
Wherein the selection unit comprises:
Only when the polarity values of all the representative pixels exceed the threshold, the input image is transmitted to the afterimage removal mode driver, or
And transmitting the input image to the afterimage removing mode driver when the polarity value of the representative pixels of a predetermined number or more of the representative pixels exceeds the threshold. Receiving a progressive input image or an interlaced input image;
Determining whether the input image causes an afterimage caused by polarity bias;
If it is determined that the input image causes an afterimage caused by polarity bias, converting the input image so as not to cause an afterimage due to polarity bias, and outputting the converted image data;
If it is determined that the input image does not cause an afterimage due to polarity bias, realigning the input image according to a panel and outputting rearranged image data; And
Converting the image data into a data voltage and outputting the data data to data lines formed on the panel. 17. The method of claim 16,
Determining whether the input image causes an afterimage caused by polarity bias,
Calculating a polarity value of the input image corresponding to the representative pixel selected as the representative pixel among the input images;
When the calculated calculated value is larger than a preset threshold, it is determined that an afterimage caused by the input image may be caused.
And if the calculated value is smaller than the threshold value, determine that the calculated value is not caused by a residual by the input image. The method of claim 17,
Determining whether the input image causes an afterimage caused by polarity bias,
In a state where the input image does not cause afterimages caused by polarity bias, the first threshold value is used to determine whether the input image causes afterimages due to polarity bias.
In the state where it is determined that the input image is causing an afterimage due to polarity bias based on the first threshold value, it is determined whether the input image is causing an afterimage due to polarity bias using the second threshold value. A liquid crystal display device driving method, characterized in that. The method of claim 17,
Determining whether the input image causes an afterimage caused by polarity bias,
The input image is transmitted to the afterimage removing mode driver only when the polarity values of all the at least two representative pixels exceed the threshold value, or
And transmitting the input image to the afterimage removal mode driver when the polarity value of the representative pixels of a predetermined number or more among the representative pixels exceeds the threshold value.

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